New therapeutical composition containing apomorphine as active ingredient

ABSTRACT

A pharmaceutical composition contains apomorphine as the active pharmaceutical ingredient, a water-miscible co-solvent, an antioxidant, and water. The solution has a pH greater than 4. The pharmaceutical composition is suitable for parenteral administration for the treatment of Parkinson&#39;s disease. The process for the manufacture of the pharmaceutical composition includes weighing the apomorphine and introducing it into a container with the co-solvent and the antioxidant under agitation until complete dissolution takes place.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of international patent application PCT/EP2012/002916, filed Jul. 11, 2012, designating the United States and claiming priority from European application 11290320.8, filed Jul. 11, 2011, and the entire content of both applications is incorporated herein by reference.

FIELD OF THE DISCLOSURE

The present invention relates to a pharmaceutical composition in the form of a solution containing apomorphine as the active pharmaceutical ingredient, and more particularly a pharmaceutical formulation for parenteral administration.

BACKGROUND OF THE DISCLOSURE

Apomorphine is a pharmaceutical active ingredient which is used to reduce “off episodes” in patients with advanced Parkinson's disease. Three solutions of apomorphine are currently marketed: a solution for subcutaneous infusion marketed under the trademark of APO-go® PFS, a solution for intermittent subcutaneous injection (bolus administration) marketed under the trademark of Apo-go® ampoules; and a solution of apomorphine for intermittent subcutaneous injection (bolus administration) marketed under the trademark of Apokyn®. These three currently marketed solutions present a pH range of 3.0-4.0.

However, these formulations induce injection site reactions. Therefore the medical precaution for their infusion is to change the injection site every 12 hours and for the bolus administration is to rotate the injection site.

Furthermore, parenteral subcutaneous injection of an active pharmaceutical ingredient (API) formulated in acidic conditions may lead to in situ precipitation and chemical degradation under physiological conditions and pH. Low pH value of the formulation, as well as potential precipitation and degradation of the drug under physiological conditions, may induce local subcutaneous site reactions as redness, etching, local indurations and nodules which are sore and troublesome. This is typically the case of apomorphine when administered in a subcutaneous (SC) infusion.

SUMMARY OF THE DISCLOSURE

To increase the local tolerance of the treatment, the applicant has found a new formulation with a pH dose to the physiological pH avoiding in situ precipitation, increasing chemical stability of the formulation and an increased drug concentration allowing the reduction of the injectable volume.

The object of the present invention is a pharmaceutical composition in the form of a solution comprising

-   -   i) apomorphine as the active substance,     -   ii) a water miscible co-solvent,     -   iii) an anti-oxidant, in particular an anti-oxidant which is         soluble in the mixture consisting of apomorphine and co-solvent,         and     -   iv) water,         wherein the pH of the composition is greater than 4.

Unless otherwise indicated the following definitions are set forth to illustrate and define the meaning and scope of the various terms used to describe the invention herein.

The term “co-solvent” as used in the present application refers to a) a solvent or a mixture of solvents which allows the incorporation of the active ingredient in the composition to obtain the required dose in a suitable volume and matches the injectability criteria or b) a water soluble solid which allows the incorporation of the active ingredient in the composition to obtain the required dose in a suitable volume and matches the injectability criteria.

The term “anti-oxidant” means a pharmaceutically acceptable compound having antioxidant properties in order to prevent oxidative degradation of the active substance and prevent oxidative degradation of the excipients.

The term “surfactant” as used herein refers to a compound or excipient with surface active properties, used mainly in the present formulations to improve the aqueous solubility of the active ingredient, help to protect the active substance against degradation and limit in vitro active ingredient precipitation if co-solvent alone is not sufficient.

The term “pH modifier” as used herein refers to a compound or excipient used mainly to adjust the pH of the formulation.

A composition according to the present invention comprises apomorphine as the active pharmaceutical ingredient (API) for active substance). The apomorphine API may be in the form of a salt or the free base.

According to the present invention it is preferred that apomorphine is in a salt form. The salts of apomorphine which can be used for the invention are preferably pharmaceutically acceptable salts of organic acids, such as those of acetic, methanesulfonic, arylsulfonic, lactic, citric, tartaric, succinic, glutamic or ascorbic acid, or pharmaceutically acceptable salts of inorganic acids, such as those of hydrochloric, hydrobromic, phosphoric, sulphuric or nitric acid.

According to another preferred embodiment of the invention apomorphine is in the form of the free base.

According to another preferred embodiment of the invention apomorphine is in a salt form, preferably apomorphine is in the form of apomorphine hydrochloride.

In a pharmaceutical composition according to the present invention, the amount of apomorphine as the active ingredient is preferably between 10 to 70 mg/mL. In another preferred embodiment, the amount of apomorphine is between 10 to 65 mg/mL. in another preferred embodiment, the amount of apomorphine as the active ingredient is selected from 10, 20, 30, 40, 50 and 60 mg/mL.

A composition according to the present invention comprises a co-solvent which allows obtaining the required injectability criteria of the pharmaceutical composition. The co-solvent is a solvent or a mixture of solvents or a water soluble solid. The co-solvent is water-miscible (Le. miscible at least at the concentration of 5% in water at 25° C.) or water-soluble, respectively. It may be selected for instance from an alcohol or a polyol such as diols, triols, mannitol, or a polyether, or a mixture thereof. When the co-solvent is an alcohol, it may be selected for instance from ethanol or isopropanol. When the co-solvent is a polyol, it may be for instance a diol such as propylene glycol, or a triol such as glycerol, or may have more than 3 hydroxyl groups such as mannitol, maltitol or cyclodextrin derivatives such hydroxypropyl-β-cyclodextrin (HPβCD) or sulfobutyl-β-cyclodextrin (SBβCD). When the co-solvent is a polyether, it may be selected for instance from polyoxyethylene glycols or polyoxyethylene glycol derivatives, such as polyoxyethylene glycol 400, Solutol® HS15 or Cremophor ® ELP.

In a preferred embodiment, the co-solvent is selected from an alcohol or a polyol or a polyether or a mixture thereof, and more preferably from polyols and polyethers or a mixture thereof. In another preferred embodiment, the co-solvent is selected from diols, triols, cyclodextrin derivatives, polyethylene glycols and polyethylene glycol derivatives or a mixture thereof. In a more preferred embodiment, the co-solvent is selected from propylene glycol, glycerol, hydroxypropyl-β-cyclodextrin (HPβCD), sulfobutyl-β-cyclodextrin (SBβCD), and polyethylene glycols derivatives or a mixture thereof.

In a preferred embodiment, the amount of co-solvent is between 0.1 to 80% (w:w) of the composition and more preferably between 0.2 to 70% (w:w).

A composition according to the present invention comprises also an antioxidant. Said anti-oxidant is preferably soluble in the mixture consisting of apomorphine and co-solvent(s). It may be selected for instance from acids and theirs salts, vitamins and derivatives, amino acids, sulfites or free phenolic radical scavengers. When the antioxidant is an acid or a salt thereof, it may be selected for instance from ascorbic acid or its salts such as sodium ascorbate, isoascorbic acid or its salts such as sodium isoascorbate, citric acid or its salts such as sodium citrate, lactic acid or malic acid. When the antioxidant is a vitamin or a vitamin derivative, it may be selected for instance from tocopherol (vitamin E), riboflavine (vitamin B2), tocopherol-PEG-succinate (vitamin derivative) or trolox (vitamin derivative). When the antioxidant is an amino acid, it may be selected for instance from cysteine, tryptophane, histidine, selenocysteine, N-acetyl cysteine, taurine, glutathione or glutathione-glutathione. When the antioxidant is a sulfite, it may be selected for instance from sodium sulfite or sodium metabisulfite. When the antioxidant is a phenolic free radical scavenger, it may be selected for instance from butylated hydroxy toluene, butyl hydroxyl anisole or cinnamic acid.

In a preferred embodiment, the antioxidant is selected from acids and their salts, vitamins and vitamin derivatives, amino acids, sulfites or phenolic free radical scavengers, and preferably from acids and their salts or sulfites.

In a more preferred embodiment, the antioxidant is selected from ascorbic acid or sodium metabisulfite, and is even more preferably ascorbic acid.

In another preferred embodiment, the antioxidant is ascorbic acid and the ratio (w:w) apomorphine/antioxidant is between 1:0.01 and 1:3.0, preferably between 1:0.03 and 1:2.0, and more preferably between 1:0.05 and 1:0.50.

In another preferred embodiment, the antioxidant is sodium metabisulfite and the ratio (w:w) apomorphine antioxidant is between 1:0.01 and 1:0.50, preferably between 1:0.03 and 1:0.30, and more preferably between 1:0.09 and 1:0.11, In a more preferred embodiment the antioxidant is sodium metabisulfite and the ratio (w:w) apomorphine/antioxidant is 1:0.10.

A composition according to the present invention may contain other additives usually used in such pharmaceutical compositions such as surfactant or pH modifier.

A composition according to the present invention may contain a surfactant or a mixture thereof. it may be selected for instance from the family of polyoxyethylene sorbitan fatty esters or polyethylene glycol derivatives or poloxamers. When the surfactant is from the family of polyoxyethylene sorbitan fatty esters, it may be selected for instance from polyoxyethylene (80) sorbitan monooleate, polyoxyethylene (20) sorbitan monolaurate, polyoxyethylene (40) sorbitan monopalmitate, polyoxyethylene (60) sorbitan monostearate. When the surfactant is a polyethylene glycol derivative, it may be selected for instance from polyethylene glycol fatty esters such as polyethylene glycol 660 12-hydroxystearate (Solutol® HS 15), or polyethylene glycol castor oil derivatives such as Cremophor® ELP.

In a preferred embodiment, a surfactant is optionally present in the composition. In another preferred embodiment, a surfactant is present in the composition. In a further preferred embodiment, the surfactant present in the composition has a hydrophile-lipophile balance (HLB) between 8 and 20 and more preferably between 12 to 17.

In a preferred embodiment, the surfactant is present in a composition according to the present invention and the surfactant is selected from the family of polyoxyethylene sorbitan fatty esters or polyethylene glycol derivatives or poloxamers. In a more preferred embodiment, the surfactant is selected from polyoxyethylene (80) sorbitan monooleate, polyoxyethylene (20) sorbitan monolaurate, polyethylene glycol castor oil derivatives, and polyethylene glycol derivative and more preferably Cremophor® ELP, or polyethylene glycol 660 12-hydroxystearate (Solutol ® HS 15).

In a preferred embodiment, the co-solvent is present in a composition according to the present invention and the apomorphine: co-solvent ratio (w:w) in the composition is between 1:0.1 to 1:40, and preferably between 1:0.2 and 1:30.

The pH of the composition is greater than 4. In a preferred embodiment, the pH of the composition is between 4 and 7, and preferably between 5 and 7. In a more preferred embodiment, the pH of the composition is between 5.5 and 6.5. In a more preferred embodiment, the pH of the composition is selected from 5.8, 5.9, 6.0, 6.1 or 6.2.

In a preferred embodiment, a pH modifier is optionally present in the composition. In another preferred embodiment, a pH modifier is present in the composition. The pH modifier may be selected for instance from sodium hydroxide, sodium bicarbonate, potassium hydroxide or magnesium hydroxide and, if necessary, acids like hydrochloric acid.

In a preferred embodiment, a pH modifier is present in the composition and it is selected from sodium hydroxide, sodium bicarbonate, potassium hydroxide or magnesium hydroxide.

A pharmaceutical composition according to the present invention is suitable to be administered by parenteral route. in a preferred embodiment, the composition of the present invention is administered by subcutaneous route, and preferably by a subcutaneous infusion.

A pharmaceutical composition according to the present invention shows a low viscosity and is easily administered by the parenteral route through 27 Gauge (G) needle and more preferably through 29 G needle.

A pharmaceutical composition according to the present invention may be useful in the treatment to reduce “off episodes” in patients with advanced Parkinson's disease.

In a preferred embodiment, the composition of the present invention is for use as medicament intented to reduce “off episodes” in patients with advanced Parkinson's disease.

The present invention is further related to the use of a composition according to the invention as injection solution, in particular as injection solution in the treatment of Parkinson's disease.

Furthermore, the invention relates to a process for the preparation of a pharmaceutical composition as described above, said process being defined by the following steps with the order below:

-   -   the optional surfactant is weighed followed by the co-solvent in         the same container;     -   the antioxidant is weighed (alone) and dissolved in degassed         water;     -   the antioxidant solution is added to the co-solvent alone or to         a mixture of co-solvent with surfactant under agitation;     -   a quantity of degassed water is added and then the solution is         adjusted to around pH 7.5±0.5 and more preferably close to pH 7;     -   the apomorphine is weighed and introduced into the above         solution and agitated until complete dissolution takes place;     -   the pH is controlled and adjusted if necessary according to the         required pH values within the range of pH 4-7, and preferably         5-7, using a pH modifier;     -   finally, the remaining quantity of degassed water is added to         reach the required volume.

The solution is preferably protected from the light. Degassed water is previously obtained by circulating and bubbling dry nitrogen gas in the solution for at least 30 minutes, and the level of oxygen in the solution is monitored using an oxymeter.

Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by a specialist in the domain associated with this invention.

The following examples are presented to illustrate the above procedures and should not be considered as limiting the scope of the invention,

EXPERIMENTAL PART Example 1 Preparation of Apomorphine Hydrochloride Solution at 40 mg/mL, Propylene Glycol (PG) (45%), Ascorbic Acid (AA) (0.4 Surfactant Polysorbate (PS80) (0.3%), pH 6

100 mL of apomorphine hydrochloride solution at 40 mg/mL is manufactured according to the following process:

-   -   0.3 g of PS80 are weighed in a flask. 45.0 g of PG are added in         the flask containing PS80;     -   in a beaker, 0.4 g of AA or 0.4 g of sodium ascorbate are         weighed. 5 g of degassed water for injection (WFI) are added to         AA or sodium ascorbate, and AA or sodium ascorbate is dissolved         in degassed water under magnetic stirring;     -   the solution of ascorbic acid is added in the flask containing         PG and PS80;

The beaker containing AA solution is rinsed with 5 g of degassed WFI. This rinsing WFI is added to the flask containing PG, PS80 and AA. The solution is homogenised under magnetic stirring.

-   -   30 g of degassed WFI are added in the flask containing PS80, PG         and AA and the solution is homogenised under magnetic stirring.         The pH is then adjusted at 7.5±0.5 using a NaOH 1 M solution (to         be as close as possible to pH 7.0);     -   4 g of apomorphine hydrochloride are weighed in a glass vial.         Apomorphine hydrochloride is introduced in the flask containing         the vehicle adjusted at pH 7.0. The glass vial containing         apomorphine hydrochloride is rinsed with 3 g of degassed WFI.         The rinsing WFI is added to apomorphine solution. Apomorphine         hydrochloride is dissolved under magnetic stirring until         complete dissolution of apomorphine hydrochloride.     -   pH of apomorphine solution is then adjusted at pH 6.0±0.2 using         a NaOH 0.1 M solution;

Apomorphine hydrochloride solution is maintained under magnetic stirring during introduction of NaOH 0.1 M solution.

-   -   Degassed WFI is added to apomorphine hydrochloride solution in         order to reach a final weight of 104.8 g of apomorphine         hydrochloride solution.

Apomorphine hydrochloride solution is homogenised under magnetic stirring and the final pH is checked.

Example 2 Stability Study of Apomorphine Solutions at 30 mg/mL and 40 mg/mL

Apomorphine content and impurities were analysed using HPLC methods. The characteristics of the HPLC method used for the apomorphine content determination are as follows:

-   -   HPLC equipment : Alliance 2695 Waters     -   Column : YMC ODS-A 5 μm, 46×150 mm, 200 Å     -   Mobile phase : 750 mL buffer : 0.03 M K₂HPO₄ pH 3     -   250 mL methanol     -   0.75 g acid L-tartaric     -   Solvent for dilution : 0.1% sodium metabisulfite (SM)     -   0.1 M HCl     -   Sparging with helium for at least 30 minutes     -   Flow rate : 1 mL/min     -   Detection : UV at 210 nm     -   Run time : 20 min     -   Temperature : Column : ambient-Carousel : 5° C.     -   Standard solution : 0.05 mg/mL     -   Injection volume : 25 μL     -   Retention time : ˜8.5 min

The characteristics of the HPLC method used for the apomorphine impurities determination are as follows:

-   -   HPLC equipment : Alliance 2695 Waters     -   Column : YMC ODS-A 5 μm, 46×150 mm, 200 Å     -   Mobile phase 875 ml buffer : 0.01 M K₂HPO₄ pH 3     -   125 mL methanol     -   0.75 g L-tartaric acid     -   Solvent for dilution : 0.1% SM     -   0.1 M HCl     -   Sparging with helium for at least 30 minutes     -   Flow rate : 1 mL/min     -   Detection : UV at 273 nm     -   Run time : 110 min     -   Temperature : Column ambient-Carousel : 5° C.     -   Standard solution : 0.0025 mg/ml     -   Injection volume : 20 μl     -   Retention time orthoquinone : ˜10 min     -   impurity A2: ˜27 min     -   impurity A1: ˜28 min     -   apomorphine : ˜35 min

The impurity content, which was determined by the area-under-the-curve calculation, is a criteria used to evaluate the stability of the prototypes.

The degree of coloration was assayed using the Eur. Pharmacopoeia colour test.

It has to be noted that the color grading (from 1 to 7) is inversely proportional to the colour intensity, i.e. 7 means a colourless aqueous solution, while 1 means a highly coloured solution,

The materials and the preparations used for this test are colour reference solutions prepared according to Eur. Pharmacopoeia.

Each below formulation (1 to 6) and its supportive stability data are reported in the following Table 1.

-   -   Formulation 1: 30 mg/mL apomorphine, 35% PG, 0.2% PS80, 0.3% SM,         pH 6.0.     -   Formulation 2: 30 mg/mL apomorphine, 35% PG, 0.2% PS 80, 0.3%         AA, pH 6.0.     -   Formulation 3: 30 mg/mL apomorphine, 35% PG, 0.3% AA, pH 6.0.     -   Formulation 4: 40 mg/mL apomorphine, 45% PG, 0.4% AA, pH 6.0.     -   Formulation 5: 40 mg/mL apomorphine, 45% PG, 0.3% PS 80, 0.4%         AA, pH 6.0.     -   Formulation 6: 30 mg/mL apomorphine, 20% HPβCD, 0.2% PS80, 0.3%         SM, pH 6.0.         (PG: Propylene glycol; PS 80: Polysorbate 80; HPβCD:         Hydroxypropyl β cyclodextrin; SM: sodium metabisulfite; AA:         ascorbic acid)

The column headings for the tables are the following:

-   -   pH;     -   degree of coloration noted as “colour;”     -   apomorphine content noted as “Est. content (mg/mL)”, since data         were obtained without using an apomorphine reference standard;         and,     -   total impurities noted as “Total imp. (%).”

TABLE 1 Test pH Colour Est. Content (mg/mL) Total imp. (%) Formu- T 3 months T 3 months T 3 months T 3 months T 3 months T 3 months T 3 months T 3 months lation T0 (25° C.) (40° C.) T0 (25° C.) (40° C.) T0 (25° C.) (40° C.) T0 (25° C.) (40° C.) 1 6.0 5.7 5.5 <B4 <B1 <JV2 29.9 29.0 28.9 <0.1 <0.1 <0.1 2 6.1 6.0 6.0 <J4 <J3 <JB3 29.2 30.3 30.1 <0.1 <0.1 <0.1 3 6.1 6.0 6.0 <J4 <J3 <JB3 30.4 30.2 30.1 <0.1 <0.1 <0.1 4 6.0 6.1 6.1 <J4 <J3 <JB3 40.7 40.1 39.9 <0.1 <0.1 <0.1 5 6.0 6.1 6.1 <J4 <JB3 <JB3 40.5 39.7 39.9 <0.1 <0.1 <0.1 6 6.0 5.8 5.7 GY6 R3/RY3 <RY1 30.8 31.0 30.3 <0.1 0.2 0.8

Example 3: In Vivo Testing

Pharmacokinetic (PK) profiles of the selected prototypes were evaluated in rats. Six cannulated rats were used for each prototype. Animals received a subcutaneous injection of the formulation at a dose of 1 mg/kg at a first injection site, a subcutaneous injection of the corresponding vehicle in a second injection site and a subcutaneous injection of saline solution in a third injection site. The injected volumes range between 0.03 to 0.2 mL/kg depending on the concentration of the formulation (0.5 to 30 mg/mL). Blood samples were collected for a 3-hour period. Plasma concentrations were determined by HPLC-MS/MS and PK parameters were calculated.

In order to evaluate the local tolerance of the tested formulations, tissues from the 3 injection sites were collected from each rat and examined by an anatomo-pathologist. A scoring from 0 to 4 (0: no effect, 1: minimal effect, 2: slight effect, 3: moderate effect, 4: severe effect) was attributed for each section and the tolerance was deduced.

The formulations as follows were administered to rats (bolus injection):

-   -   Reference: Apo-go® PFS 5 mg/mL, pH 3.3     -   Test 1: 29.12 mg/mL apomorphine, 20% SBβCD, 0.3% SM, pH 5.9.     -   Test 2: 10 mg/mL apomorphine, 0.2% PS 80, 0.1% SM, pH 4.2.     -   Test 3: 29.36 mg/mL apomorphine, 0.2% PS 80, 30% PG, 0.3% SM, pH         6.0.     -   Test 4: 29.36 mg/mL apomorphine, 20% HPβCD, 0.2% PS 80, 0.3% SM,         pH 5.9.     -   Test 5: 29.36 mg/mL apomorphine, 0.2% PS 80, 30% PG, 0.3% SM, pH         4.1         (PG:Propylene glycol; PS 80:Polysorbate 80;         SBβCD:Sulfobutylether β cyclodextrin; HPβCD:Hydroxypropyl β         cyclodextrin; SM:sodium metabisulfite)

These selected prototypes were compared to the reference solution (APO-go®) regarding the PK profile and the local tolerance.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the drawings wherein:

FIG. 1 (details of the absorption phase of tested formulations (1 mg/kg, SC in rats)) shows the plasma profile of apomorphine over the first 14 minutes in order to obtain the PK parameters of the absorption phase.

FIG. 2 (PK profiles of tested formulations (1 mg/kg, SC in rats)) shows the overall plasma profile of apomorphine over a 3-hour period.

DESCRIPTION OF THE BEST AND VARIOUS EMBODIMENTS

The PK parameters of these tested formulations in rats (1 mg/kg-SC) are presented in the Table 2.

TABLE 2 APO- Parameter go ® Test 1 Test 2 Test 3 Test 4 Test 5 Concentration 5.0 29.1 10.0 29.4 29.4 29.4 (mg/mL) pH 3.3 5.9 4.2 6.0 5.9 4.1 Cmax (ng/mL) 242 150 211 191 357 182 Tmax (min) 5 11 4 4 5 9 AUC (ng · h/mL) 104 98 99 85 136 113 Bioavailability (%) Reference 94 95 82 130 108 Cmax: maximum value of the apomorphine concentration in the rat serum. Tmax: time after administration for the apomorphine concentration to reach the Cmax value. AUC: area under the curve of the PK profile vs time.

The total apomorphine exposure for the above tested formulations was quite similar with regard to the reference, and no major PK differences can be observed for the five test formulations, which are significantly more concentrated than the reference APO-go® formulation. Consequently all of them show an acceptable profile from a PK point of view.

Example 4 Local Tolerance

The local tolerance results of the tested formulations in rats (1 mg/kg-SC) are presented in the Table 3.

TABLE 3 APO- Test Test Test Test Test Parameter go ® 1 2 3 4 5 Concentration (mg/ml) 5.0 29.1 10.0 29.4 29.4 29.4 pH 3.3 5.9 4.2 6.0 5.9 4.1 Tolerance formulation 2.7 2.4 3.7 2.3 3.0 3.2 scoring placebo 0.3 0.6 0.5 0.3 0.2 0.8 Note: tolerance scoring for the saline solution was 0.1.

The same tolerance level than the Apo-go® reference is observed for the 5 test formulations, which have a concentration from 2 to 6 times higher than the reference (from 10 to 30 mg/mL for the test formulations vs. 5 mg/mL for the reference).

Thus, using a formulation according to the present invention, patients will be able to receive a better treatment based on a 6-fold lower injection volume, a formulation at a more physiologically acceptable pH and a formulation that tends to be more tolerated than the APO-go® reference.

Example 5: 14-Day Subcutaneous Infusion in Vivo Testing

PK profile of the selected prototypes were evaluated in rats. Subcutaneous micropumps were implanted in 6 rats for each prototype. Micropumps were implanted subcutaneously in the lumbar region for continuous infusion in the scapular region. Animals received a subcutaneous infusion of the formulation at a dose of 6 mg/kg/day (0.3 mg/kg/hour) of the appropriate apomorphine formulations to animals over a 20 h period/day for 14 days. Blood samples were collected at the following time point:

-   -   Day 1 at 0 h, 6 h post Start of Infusion and 20 h post Start of         Infusion (SOI),     -   Day 7 20 h post Start of Infusion (SOI),     -   Day 14 at 0 h, 20 h post Start of Infusion (SOI).

Plasma concentrations were determined by HPLC-ESI-MS/MS method and PK parameters were calculated.

In order to evaluate the local tolerance of the tested formulations, tissue from the injection site were collected from each rat and examined by an anatomo-pathologist. A scoring from 0 to 4 (0:no effect, 1:minimal effect, 2:slight effect, 3:moderate effect, 4:severe effect) was attributed for each section and the tolerance was deduced.

The formulations as follows were administered to rats (infusion injection):

-   -   Test 1 (reference): Apo-go® PFS 5 mg/mL, pH 3.3     -   Test 2: 30 mg/mL apomorphine, 35% PG, 0.2% PS80, 0.3% SM, pH         6.0.     -   Test 3: 30 mg/mL apomorphine, 35% PG, 0.2% PS 80, 0.3% AA, pH         5.8.     -   Test 4: 30 mg/mL apomorphine, 35% PG, 0.3% AA, pH 5.9.     -   Test 5: 40 mg/mL apomorphine, 45% PG, 0.4% AA, pH 5.9.     -   Test 6: 40 mg/mL apomorphine, 45% PG, 0.3% PS 80, 0.4% AA, pH         5.9.         (PG:Propylene glycol; PS 80:Polysorbate 80; SM:sodium         metabisulfite; AA:ascorbic acid)     -   These selected prototypes were compared to the reference         solution (APO-go®, Test 1) regarding the PK profile and the         local tolerance.

The PK parameters of these tested formulations in rats (6 mg/kg/day-SC continuous infusion) after day 1, 7 and 14 are presented in the Table 4.

TABLE 4 Test 1 (Refer- Parameter ence) Test 2 Test 3 Test 4 Test 5 Test 6 Concentration 4.58 28.9 29.6 30.4 39.5 37.2 (mg/mL) pH 3.3 6.0 5.8 5.9 5.9 5.9 C_(maxss) (ng/ml) 12.95 17.16 13.43 12.19 13.51 10.02 on day 1 C_(maxss) (ng/ml) 10.35 13.01 9.79 11.53 7.17 9.25 on day 7 C_(maxss) (ng/ml) 15.21 9.68 8.73 7.30 2.76 9.54 on day 14

C_(maxss): is the maximum concentration of apomorphine in plasma at steady-state conditions. The value on day 1 were calculated as the mean of all concentration values obtained at 6 and 20 hours Post-start of infusion (SOI) (2 sample time points). At the 7^(th) infusion day, C_(maxss) is the mean of all concentration values at day 7 (single sample time point). At the 14^(th) infusion day, is the mean of all concentration values at 20 h Post-SOI, i.e. at the end of infusion (EOI) (single sample time point).

Apomorphine exposure data of above tested formulations were similar with regard to the reference.

The PK parameters of these tested formulations in rats (6 mg/kg/day-SC continuous infusion) on day 14 are presented in the Table 5.

TABLE 5 Test 1 (Refer- Parameter ence) Test 2 Test 3 Test 4 Test 5 Test 6 Concentration 4.58 28.9 29.6 30.4 39.5 37.2 (mg/mL) pH 3.3 6.0 5.8 5.9 5.9 5.9 C_(maxss) (ng/ml) 15.2 9.68 8.73 7.30 2.76 9.54 on day 14 AUC (ng · h/ml) 277 210 178 183 75 173

C_(maxss) corresponds to the mean concentration obtained after 20 h Post SOI

No major PK differences can be observed for the five test formulations. Consequently all of the test formulations show an acceptable profile from a PK point of view.

Example 6: Local Tolerance in the 14-Day Subcutaneous Infusion Experiment

The local tolerance data of the tested formulations in subcutaneous infusion over 20 h/day in rats at 6 mg/kg/d are presented in the Table 6. The tolerance scoring was established at the 14^(th) day of infusion, i.e., at the EOI.

TABLE 6 Test 1 Parameter (Reference) Test 2 Test 3 Test 4 Test 5 Test 6 Concentration 4.58 28.9 29.6 30.4 39.5 37.2 (mg/mL) pH 3.3 6.0 5.8 5.9 5.9 5.9 Tolerance scoring 3.0 2.8 2.3 2.7 2.4 2.6

The same tolerance level than the Apo-Go® reference (Test 1) was obtained with the test formulations that show a 6 to 8 times higher concentration.

Thus, using a formulation according to the present invention, patients will be able to receive a better treatment based on a 6 to 8 times lower injection volume, a formulation at a more physiologically acceptable pH and a formulation that. tends to be more tolerated than the APO-go® reference.

It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims. 

1. A pharmaceutical composition having an active substance and being provided in the form of a solution, the pharmaceutical composition comprising: i) apomorphine as the active substance; ii) a water miscible co-solvent; iii) an antioxidant; and iv) water; wherein a pH of the composition is greater than
 4. 2. The composition of claim 1, wherein an amount of the active substance is between about 10 to 70 mg/ml.
 3. The composition according to claim 1, wherein an amount of the water miscible co-solvent is between 0.1 to 80% (w:w) of the composition.
 4. The composition according to claim 1, wherein the water miscible co-solvent is selected from the group consisting of an alcohol, a polyol, and a polyether or a mixture thereof.
 5. The composition according to claim 1, wherein the co-solvent is selected from a diol, a triol, a cyclodextrin derivative, a polyethylene glycol, and a polyethylene glycol derivative or a mixture thereof.
 6. The composition according to claim 1, wherein the antioxidant is selected from the group consisting of an acid, a salt thereof, a vitamin, a vitamin derivative, an amino acid, a sulphite, and a phenolic free radical scavenger.
 7. The composition according to claim 1, wherein the antioxidant is selected from the group consisting of ascorbic acid and sodium metabisulfite.
 8. The composition according to claim 1, wherein the pharmaceutical composition further comprises a surfactant.
 9. The composition of claim 8 wherein the surfactant has a hydrophile-lipophile balance (HLB) between 8 and
 20. 10. The composition of claim 8, wherein the surfactant is selected from the group consisting of a polyoxyethylene sorbitan fatty ester, a polyethylene glycol derivative, and a poloxamer.
 11. The composition according to claim 1, wherein an apomorphine:co-solvent ratio (w:w) is between 1:0.1 to 1:40.
 12. The composition according claim 1, wherein the pH of the composition is between 4 and
 7. 13. The composition according to claim 1, wherein the composition further comprises a pH modifier.
 14. The composition according to claim 13, wherein the pH modifier is selected from the group consisting of sodium hydroxide, sodium bicarbonate, potassium hydroxide, and magnesium hydroxide or a mixture thereof.
 15. A method of administering the composition according to claim 1 to a patient in need thereof, wherein the composition is administered by parenteral route.
 16. A method of reducing “off episodes” in a patient with advanced Parkinson's disease comprising administering the composition according to claim
 1. 17. An injection solution for the treatment of Parkinson's disease comprising the composition according to claim
 1. 18. A process for the manufacture of the composition according to claim 1, the process comprising: providing a first container; ii) optionally, weighing a surfactant in the first container; iii) adding the co-solvent to the first container; iv) weighing the antioxidant in a second container and dissolving the antioxidant in degassed water to obtain an antioxidant solution; v) adding the antioxidant solution to the first container under agitation; vi) adding degassed water to the first container and adjusting the pH to about 7.5±0.5; vii) weighing the apomorphine and introducing the apomorphine to the first container under agitation until complete dissolution takes place; viii) controlling the pH of the solution in the first container within the range of 4 to 7 by adding a pH modifier as necessary to maintain the pH within the range; and, ix) adding a remaining quantity of degassed water to reach a predetermined volume of the solution. 